Irradiated Glass, the Amethyst Color of Greed

Sometimes called desert glass, or sun-colored amethyst glass, these pretty purple bottles are fake; their color is artificially produced by gamma radiation in a lead lined chamber by an unscrupulous merchant with one motive – profit.

Irradiated glass is a problem for bottle collectors and a nightmare for insulator collectors. That’s because there are so many irradiated insulators on eBay and some are gorgeous and exhibit previously unknown colors. Even though some sellers do admit their insulators have been ‘altered’, the foremost objective of their fakery is immediate profit with no regard for the effects on the insulator collecting hobby.

Thankfully, experts like Dwayn Anthony at the National Insulator Association have created a comprehensive collection of fakes to help warn amateur enthusiasts; over the past six years they've conducted extensive research and subjected many different makes and models of insulators to different types of radiation to photograph and catalog the results.

Radiation of old glass produces colors without historical precedent. It isn’t natural and it's irreversible. It isn't natural because no druggists bottles, cough medicines, hair tonics, lotions, whiskeys or sodas were ever made that color amethyst, or in those particular shades of cobalt blue, or those unnatural shades of amber... A rare or unusual color today probably means that somebody somewhere tampered with the chemical composition of the glass (using gamma radiation) to make it a unique specimen, and now unfortunately that piece is ruined forever.

Here is a Digger on eBay selling irradiated glass which he admits is altered (but not in the headline, and only after suggesting that it could be the product of the sun's own ultraviolet light) and his page contains some information about the history of manganese in glass making. He should probably stop this practice altogether... Dumpdiggers is of the opinion that Digger Dave is ruining the historic glass he finds, while fostering deception.

Here's a Ball fruit sealer jar that's a weird color of amber... Dumpdiggers found this on BallJars.net after doing a Google search on the words ‘irradiated glass bottle’. Don’t give this guy a hard time though as I don't believe he's the source of these irradiated fruit sealer jars.

The Chemistry of Glass is at the core of this controversy, and the history of North American glassmaking is subdivided by the price of lead and the US Civil War. You see up until the 1860's lead had always been used as the principle clarifying agent (vitrifying) in making clear glass from what would otherwise be green glass (due to iron impurities in sand).

Even before the American Civil War 1861-1864, the element Lead Pb was a valuable strategic commodity and used for all manner of industrial applications, the most important being the manufacture of munitions. But lead was also used to line the insides of British East India tea boxes, and as the principle ingredient in white paint and clear glass. In the industrial markets of London in the summer of 1853, the price of pig lead climbed from £17.77 all the way up to £23.40 per ton and eventually peaked at £24 in the spring of 1856 - the rise was affected in part by the Crimean War 1853-56. The price of lead affected the price of glass in England and North America. During the 1850’s, almost all of the small glasshouses that had appeared along the new railway lines in Upper and Lower Canada failed.

In 1864 William Leighton, a son of Thomas Leighton developed a successful soda lime formula for glass that didn’t require lead.

From this point on all North American glasshouses were classified as either flint glass (with lead), or green glass houses which used soda lime. The New England Glass Company in Boston is probably the most famous lead glass house.

1860 – 1880 Canadian Glass Houses

Of the four dominant glass companies operating in the early 1860s, the Canada Glass Works in Hudson, Qué, 1864-72, and the Hamilton Glass Company, Hamilton, Ont, 1865-96, were "green" glasshouses that used Leighton's soda lime recipe to make green hued window glass and bottles which ranged in colour from aqua through green to olive green and amber.

The St Lawrence Glass Company, Montréal, 1867-73, and the Burlington Glass Company 1874-98 in Hamilton, Ontario however were lead / flint glass houses.

Flint is a colourless glass mineral that occurs in nature and has been known since ancient times – flint is a sedimentary cryptocrystalline form of quartz, and is categorized by geologists as a variety of chalcedony or ‘chert’ which can sometimes contain fossilized shellfish. Flint is usually dark-grey, black, or deep brown in color and when crushed into powder and added to molten sand and soda mixture it becomes a decolorizing agent that masks out the natural iron molecular impurities present in every grain of sand.

Because of the high price of lead in the 1860’s, pure manganese and manganese dioxide (specifically the mineral pyrolusite which is the primary ore of manganese and occurs as black or dark bluish-gray powder) was substituted as the glass makers 'soap’ - the element worked just as well as lead to counteract the green discoloration caused by impurities. (Pure manganese is a silvery white brittle metal that does not occur in nature and was not isolated and identified as an element until 1774 – pure manganese was exported from Germany to England and America between 1880 and1914 - this was the great era of manganese glass. )

Manganese was the most common vitrifying agent in clear glass made in the American industrial revolution – it was used right up until World War One and war with Germany cut North American supplies. It was at this time that selenium was discovered and soon replaced manganese as the vitrifying agent of choice in clear glass.

When exposed to the radioactive isotopes Cobalt-60 and Cesium-137, most manganese glass will turn amethyst, while glass made with selenium will become either straw, wheat, or honey colored.

Irradiated Glass in rural Canadian Antiques Markets

A few years ago Dumpdiggers went shopping for early Canadian glass bottles at the Aberfoyle Antiques Market in Southern Ontario, Canada – it was July 2001, and while wandering the 'antiques village', this author spotted three separate displays of irradiated glass showcased in various windows and doorways and being sold at premium prices. Upon questioning the vendors, Dumpdiggers learned that all three shopkeepers had bought the merchandise from the same individual, on the same day.

That fakery isn’t tolerated in Toronto, and so 'sun-coloured amethyst' glass ends up out in the country bazaars, at village antique shops and flea markets where the vendors are hobbyists and the customers are tourists or cottagers with summer homes in the area. Out there the dealers feign ignorance when you point and ask ‘Is that glass irradiated?’